Rolling mill roll changing



H. BOHNENKAMP EI'AL ROLLING MILL ROLL CHANGING Nov. 24, 1970 Filed May 17, 1968 FIG.|

3 She sis-Sheet 1 INVENTORS HEINRICH BOHNENKAMP OTTO MODDER ATTORNEY 24, 1970 H. BOHNENKAMP ETAL ,830

ROLLING MILL ROLL CHANGING Filed May 17", 1968 3 Sheets-Sheet 2 FIG. 3

e W w j um #6 INVENTORS HEINRICH BOHNENKAMP H. BOHNENKAMP E AL 3,541,830

ROLLING MILL ROLL CHANGING Nov. 24, 1970 3 Sheets-Sheet 3 Filed May 17, 1968 FIG. 5

liwik INVENTORS HEINRICH BOHNENKAMP OTTO MODDER ATTORNEY United States Patent Ofice 3,541,830 Patented Nov. 24, 1970 s Int. Cl. B2ib 31/10 U.S. Cl. 72-238 7 Claims ABSTRACT OF THE DISCLOSURE This disclosure provides a work roll chock configuration for a 2- or 4-high rolling mill to facilitate changing of the work rolls as a unit from the mill. The upper work roll chocks have lower surfaces constructed at each side of the chocks with stepped surfaces such that in the direction of the roll axes one surface projects from the chock relative to the other surface. The lower work roll chocks have upper surfaces constructed at each side of the chocks with stepped surfaces such that in the direction of the roll axes one surface is recessed in the chock relative to the other surface. During the rolling operation, the stepped surfaces complement each other and, during roll changing, the lower roll and chocks are axially shifted to form a stable roll unit by locating the projecting surfaces of the upper roll chocks on the nonrecessed surfaces of the lower roll chocks.

BACKGROUND OF THE INVENTION In a rolling mill it is well known in the art to provide roll housings to support and guide bearing chocks for a pair of work rolls. These chocks are designed in such a manner that, incident to the rolling operation, the opening between the rolls can be adjusted, usually from a dimension of zero upward to a certain limit. As a result of this design, when the rolls and their chocks are being removed and inserted into the housings as a unit, the bodies of the rolls would normally be in supporting contact with each other and a clearance would exist between the bearing chocks at each side of the housing.

During replacement of the work rolls and chocks, in order to prevent damage to the roll bodies and prevent the upper roll from rolling about the roll body of the lower roll, which would occur until the clearance is eliminated between the chocks, it is a common practice to insert spacers between the chocks before changing the rolls. These spacers are designed and dimensioned so that the upper and lower roll bodies are located at a predetermined distance from each other during changing of the rolls, which is accomplished with any well-known form of roll changing apparatus. The spacers are, under common practice, placed between the chocks manually by a workman, resulting in a cumbersome and time-consuming task because not only must suitably dimensioned spacers be available in advance of roll changing, but also the insertion and removal of the spacers must be performed manually at certain areas of the mill that are not readily accessible.

In another form of the prior art, with respect to changing the work rolls of a 4-high rolling mill, the upper work roll chocks are supported by the lower work roll chocks, which are then supported by lower backup roll chocks carried by a sled that traverses both the work roll and lower backup roll into and out of the housing. In this form of roll changing, it has been suggested to separate the roll bodies by employing the conventional roll balance hydraulic piston cylinder assemblies provided between the work roll chocks and the chocks of the lower work roll and backup roll in order to eliminate the use of the aforementioned spacers. This form of roll changing permits quick raising and aligning of the work rolls, but it is considered undesirable because, incident to changing the rolls, the conduit lines for the hydraulic piston cylinder assemblies must be manually disconnected and connected from a source of pressure medium.

It is also known in the art of 4-high rolling mills to construct the chocks of the upper work roll with downwardly projecting legs that partly encompass the chocks of the lower work roll by which they are carried when the upper work roll chocks are lifted. With this construction it becomes necessary, when changing the work rolls, to provide rails carried by the upper backup roll chocks to support the work rolls during their removal. This not only requires a more complicated design for the roll chocks but it also requires a comparatively wide housing window, especially for rolling mills in which narrow widths of stock are being rolled. Moreover, it is a cumbersome operation to change the work rolls of a 4-high rolling mill when the lower work roll chocks are suspended from the upper work roll chocks which are, in turn, suspended from rails of the upper backup roll chocks.

It is one object of this invention to provide an improved rolling mill stand wherein the procedure of changing the rolls can be accomplished without performing cumbersome and time-consuming manual work.

It is another object of the present invention to provide a design for rolling mill chocks of a pair of work rolls, such that without'resorting to separate spacers, the rolls are maintained at a predetermined distance from each other during the process of removing and replacing the rolls in the mill housings.

SUMMARY OF THE INVENTION According to the present invention, there is provided a rolling mill comprising a pair of housings having windows for receiving upper and lower roll assemblies, including an upper roll having a bearing chock at each end supported by the housing and a lower roll having a bearing chock at each end supported by the housing, each of the upper roll chocks having stepped lower surfaces, one surface recessed relative to the other in the direction of the axis of the upper roll. Each of the lower roll chocks have stepped upper surfaces, one surface projecting relative to the other in the direction of the axis of the lower roll. The stepped surfaces of the upper roll and the lower roll chocks complement each other when in their operative locations, and means for axially displacing the lower roll assembly relative to the upper roll assembly to position the nonrecessed and projecting surfaces of the respective chocks above each other for mutual supporting contact to thereby maintain the upper roll spaced from the lower roll.

There are also provided roll adjusting screws or hydraulic roll balancing piston cylinder assemblies for lifting of the upper roll assembly in the roll housing prior to axial movement of the lower roll assembly, which is preferably accomplished by the roll changing device.

In another aspect according to the invention, ledge-type protrusions project into the housing windows on both sides in which are mounted hydraulic roll elevating means to effect the lifting of the upper roll assembly incident to changing the rolls and for balancing the weight of the upper roll assembly during the rolling operation.

A further aspect of the present invention resides in constructing the relative height of the stepped surfaces in the lower roll chocks greater in magnitude than that of the complementary stepped surfaces in the upper roll chocks, whereby during the rolling operation, the opening between the rolls can be adjusted to a dimension of zero and during the changing of the rolls, the rolls are held out of mutual contact.

The present invention also provides that the stepped surfaces of the lower work roll chocks are arranged such that the nonrecessed surface adjoins the body portion of the roll at the operators side of the mill and, at the drive 1said; of the mill, the recessed surface adjoins the roll According to a further characteristic of the present invention, the stepped surfaces in each of the upper and lower roll chocks are constructed in equally-spaced vertical planes spaced from the vertical plane containing the rotational axes of the rolls.

DESCRIPTION OF THE DRAWINGS These objects, as well as other features and advantages of the present invention, will be better appreciated when the following description thereof is read in light of the accompanying drawings, of which:

FIG. 1 is an elevational view of a Z-high mill incorporating the features of the present invention,

FIG. 2 is an elevational view similar to FIG. 1 but illustrating the upper roll lifted from its operational position and a lower roll axially shifted,

FIG. 3 is an elevational view similar to FIG. 2 illustrating the upper and lower roll positioned for changing the rolls as a unit from the roll housings,

FIG. 4 is an enlarged sectional view taken along line IV-1V of FIG. 1, and

FIG. 5 is a side elevational view of a second embodiment of the present invention relating to a 4-high rolling mill stand.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1 of the drawings, there is illustrated the essential components of a rolling mill constructed in accordance with the present invention. In the windows 1 formed in the rolling mill housings 2 there is located an upper roll 3 supported in the housing by bearing chocks 5. A lower roll 4 is supported in the housings by the bearing chocks 6. The bearing chocks 5 of the upper roll are suspended from the ends of adjusting screws 7, while the bearing chocks 6 of the lower roll rest against adjusting screws 8. The screws 7 and 8 serve to adjust the roll opening and simultaneously take the rolling pressure. The screws 7 illustrated in FIG. 1 are also employed to lift the upper roll 3 by its chocks 5 when the rolls 3 and 4 are to be removed as a unit from the roll housings.

In order to separate the rolls 3 and 4 from each other during roll changing, the upper roll bearing chocks 5 are constructed on their lower surface with stepped surfaces 9 and 10, the surface 10 projecting from the surface 9. The lower roll bearing chocks 6 are constructed with stepped surfaces 11 and 12 arranged such that the surface 12 is recessed relative to the surface 11.

During the rolling operation when the opening between the rolls 3 and 4 is decreased to a predetermined minimal dimension, the surfaces 9 and 10 of the chocks 5 assume a meshing relationship with the surfaces 11 and 12 of the chocks 6. The height or change in elevation between the surfaces 9 and 10, and also surfaces 11 and 12, is such that the opening between the rolls 3 and 4 can be reduced to zero during the rolling operation without the surfaces 9 contacting the surfaces 11 and the surfaces 10 contacting the surfaces 12.

It will be noted that from viewing FIGS. 1, 2 and 3 that the surfaces 10, which are projecting from the chocks 5, and the surfaces 12, which are recessed in the chocks 6, are located towards the operators side of the mill, which is to the left of the surfaces 9 and 11. As shown in FIG. 4, the stepped surfaces 9 and 10, and also 11 and 12, do not extend the full width of their respective chocks. It will be noted that the surfaces 10 projecting from the 4 chocks 5 and the surfaces 12 recessed in the chocks 6 extend only a short distance across the width of the chocks from their outside vertical surfaces. In contrast to this the surfaces 9 recessed in the chocks 5 and the surfaces 11 projecting from the chock 6 extend over a substantial part of the chocks total width.

To efiect changing of the rolls according to the present invention, the chocks 5 for the upper roll 3 are positioned to be supported on the chocks 6 for the lower roll 4, in which position the stepped surfaces 10 projecting from the chocks 5 engage the surfaces 11 on the chocks 6. In this manner, the rolls 3 and 4 are separated from each other to not only prevent damage to their working surface that would otherwise occur if in mutual contact, but also the rolls and chocks are arranged as a stable unit to facilitate their removal and replacement. In order to locate the rolls and chocks in this position, the upper roll 3 is lifted by the screws 7 until the surface 10 of the chocks 5 is raised above the surface 11 of the chocks 6. After this occurs, the lower roll 4 and its chocks 6 are displaced in an axial direction by a roll changing device 13, per se well known in the art, until the surfaces 11 are vertically aligned with the surfaces 10 as illustrated in FIG. 2. The upper roll and chocks are then lowered by the screws 7 until the surfaces 10 engage the surfaces 11, which relative position is illustrated in FIG. 3. In this position, the rolls 3 and 4 with their chocks can be readily pushed from the housing Windows 1 by the device 13 and a similarly arranged pair of replacement roll assemblies can be pulled into the windows of the mill housings.

Thus, the present invention enables changing of rolls without requiring the use of manual labor by remote control of the screws and the roll changing device. This has an additional advantage of reducing the time required to change the rolls.

FIG. 5 illustrates a 4-high rolling mill stand and represents a second embodiment of the present invention wherein a different means is provided for moving the chocks vertically. In this embodiment, the upper work roll 3' is elevated by the hydraulic piston cylinder assemblies 14 which also serve during the rolling operation to balance the weight of the upper roll. These piston cylinder assemblies are carried by projections 15 protruding from the housing Windows 1'. In this arrangement, the rolls are changed without requiring the disconnection of hoses and the like for transmitting the hydraulic pressure mediunn to the piston cylinder assemblies. Also received into the projections 15 are roll adjusting piston cylinder assemblies 17, which are employed to urge the lower work roll 4 towards the lower support roll in addition to raising the lower work roll 4 from the lower support roll during changing of the Work rolls.

In accordance with the provisions of the patent statutes, we have explained the principle and operation of our invention and have illustrated and described what we consider to represent the best embodiment thereof. However, we desire to have it understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. A rolling mill comprising:

a pair of housings having windows formed therein;

a pair of work rolls;

a bearing chock mounted on each end of said work rolls received in said windows;

a projecting surface extending from each chock of one of said work rolls having a dimension normal to the axis of the roll sufficient to keep a bearing chock supported thereby from tilting;

a recessed surface projecting into each of the chocks of the other work roll opposite the side of the chocks having said projecting surfaces and having a dimension normal to the axis of the roll and greater than said dimension of said projecting surfaces;

:1 support surface formed on each of the chocks of said other work roll opposite the side of the chocks having said projecting surfaces and having a dimension normal to the axis of the roll sufficient to keep the projecting surfaces from tilting when engaged therey;

roll removal means for displacing said other work roll into a first and second axial position relative to said housings and said one work roll; and

means for causing said projecting surfaces of the chocks of said one work roll and the support surfaces of the chocks of said other work roll to engage each other, thereby allowing the chocks of the one work roll to be supported by the chocks of the other work roll when said roll removal means displaces the other work roll to said first position and thereafter on further displacement by said roll removal means to carry the one work roll to said second position.

2. A rolling mill according to claim 1 wherein said means for causing the chocks to engage each other comprises adjusting screws engaging the chocks for said one work roll.

3. A rolling mill according to claim 1 wherein said recessed surfaces project into the surfaces of the chocks of said other work roll a distance greater than the distance said projecting surfaces extend from the surfaces of the chocks of said one work roll.

4. A rolling mill according to claim 1 wherein one of the projecting surfaces of the chocks of said one work roll is disposed adjacent the body portion of said one work roll and the projecting surface of the other chock of said one work roll is disposed adjacent the end of the one work roll.

5. A rolling mill according to claim 1 wherein each chock for said one work roll includes projecting surfaces horizontally spaced from the vertical plane containing the axis of rotation of said work rolls.

6. A rolling mill according to claim 1 further comprising:

housing projections horizontally extending into said windows and arranged between the chocks for said work rolls;

said means for locating comprising piston cylinder assemblies carried by said housing projections.

7. A rolling mill according to claim 6 comprising:

an upper supporting roll assembly including an upper backup roll and bearing chocks for supporting said one work roll; and

a lower supporting roll assembly including a lower backup roll and bearing chocks for supporting said other work roll.

References Cited UNITED STATES PATENTS 2,140,929 12/1938 Talbot 72-239 3,309,909 3/1967 Wilson 72--248 RICHARD J. HERBST, Primary Examiner B. J. MUSTAIKIS, Assistant Examiner 

